Incorrectly parse hexa to rgba to hexa

[MrKou47]

actual:

const expectValue = '#cc88'
colord(colord(expectValue).toRgbString()).toHex() !== expectValue // #cccc8887

expect:

const expectValue = '#cc88'
colord(colord(expectValue).toRgbString()).toHex() !== expectValue // toHex() return value should equal to expectValue